Diaphragm valve



March 21, 1967 H. w. BOTELER 3,310,280

DIAPHRAGM VALVE Filed Nov. 16, 1965 I 4 Sheets-Sheet l INVENTOR. HENRYw. BOTELER F E G 2 ATTORNEY March 21, 1967 H w, BOTELER 3,310,280

' ,DIAPHRAGM VALVE Filed Nov. 16, 1965 4 Sheets-Sheet 2 INVENTOR. HENRYW. BOTELER ATTORNEY March 21, 1967 H. w. BOTELER DIAPHRAGM VALVE -4Sheets-Sheet 5 Filed Nov. 16, 1965 INVENTOR. HENRY W. BOTELER ATTO EYMarch 21, 1967 H. w. BOTELER 3,310,280

DIAPHRAGM VALVE Filed Nov. 16, 1965 4 Sheets-Sheet 4 FIG.7

INVENTOR. HENRY W; BOTELER ATTORNEY United States Patent 3,310,280DIAPHRAGM VALVE Henry W. Boteler, East Greenwich, R.I., assignor toGrinnell Corporation, rovidenee, ILL, a corporation of Delaware FiledNov. 16, 1965, Ser. No. 5%,041 Claims. (Cl. 251-331) This application isa continuation-in-part of application Ser. No. 315,817, filed Oct. 14,1963, and entitled, Diaphragm Valve, now abandoned.

This invention relates to improvements in diaphragm valves. Moreparticularly, it has to do with a diaphragm valve in which there is asharp reduction in the crosssectional area of the flow between the inletend of the passage and the valve seat when the valve is in the openposition. With such a construction, and especially with such aconstruction in which the reduction is located as close as possible tothe seat, a characteristic flow curve is achieved which is much moresuitable for control valve applications than the prior art diaphragmvalves.

A typical diaphragm valve of the kind to which the present inventionrelates has a body with a flow passage therethrough between its inletand outlet ends, with a diaphragm opening on one side of said body andcommunicating with said passage and with a seating on the interior wallsurfaces of said body opposite said diaphragm opening. The seating isessentially a narrow concave band with ends merging into the rim of thediaphragm opening at about the level of the axis of the end openings,with steeply sloping end portions extending down into the body from saidends and with a concave center portion. The seating band may have itscenter portion on a level with the interior walls elsewhere along thebody interior or it may be slightly raised above such level. From theseating ends the body opening rim slopes upwardly to opposite pointsabove the axis referred to. A diaphragm having its periphery clamped tothis opening rim and having its steeply domed central portion oppositethe seating achieves valve closure by being pressed against the seatingband and achieves valve opening by being withdrawn from such surface.The diaphragm movements are achieved by a compressor adjacent the backside of the diaphragm and secured to the center thereof. This compressorand other parts of the actuating mechanism are housed in a bonnet whichserves to clamp the diaphragm periphery as above described.

To those familiar with this kind of diaphragm valve it is well knownthat the area of the diaphragm opening in this kind of valve has alwaysbeen of such shape and size that the cross-sectional area of the flowpassageway is greatly increased at the seat.

Stated another way, with a deeply bulged diaphragm having the usualgenerally circular center portion the area of this portion has alwaysbeen relatively large, for example, much larger than the area of thefiow passage inlet or outlet openings. The reason for this prior artconstruction is clear. In order to provide as little obstruction to flowas possible the center portion of the seating band has usually hadsubstantially the same curvature as the portions on either side of it,and hence when the side portions of this seating band have slopedsufliciently to permit a rolling action of the domed central diaphragmcentral portion the body diaphragm opening which has been required forsuch a diaphragm has had an area much greater than the area of each ofthe end openings. Consequently the distance across the diaphragm openingbetween the ends of the sea-ting bands has been so great in the priorart valves of this no-weir or low-weir type that the area of the flowpassage at the seating has been far greater than the area of the flowpassage at the body end openings. However, this large flow passage areaat the 3,3132% Patented Mar. 21, 1967 seating when the valve is open hasnot bee-n regarded as a disadvantage in the prior art valves of thistype. On the contrary, the increase in such area at the seating has beenwelcomed as an aid to free flow, and even where attempts have been madeto decrease the size of the bodys diaphragm opening in order to make thevalve less-ex- I pensive the distance between the seating ends (diameterof the body diaphragm opening) has still been greater than the diametersof either of the end openings with the result that the area of thediaphragm opening has been greater than the area of either of the endopenings.

Where the prior art has employed a low weir and the concavity of thedomed central diaphragm portion has been great the area of the diaphragmopening (still generally circular) has also been much larger than thearea of either of the passage ends because of the necessity to provide aslope on the sides of the seating which will permit a rolling action ofthe domed central diaphragm portion and also because it has beenimportant in this kind of valve to avoid any reduction in thecross-sectional area of the flow passage when the valve is open. Thus,even though there have been efforts to reduce the size of the diaphragmopening in no-Weir valves, the diaphragm openings in such valves havestill been considerably larger than the inlet or outlet openings inorder to avoid any passage area reduction.

The present invention results from my discovery that by sharply reducingthe cross-sectional area of the flow passage between the inlet openingand the seat, and preferably by locating this reduction as close aspossible to the seat a characteristic curve (flow vs. stem position)results which is much more useful in control work than thecharacteristic curves of the prior art diaphragm valves.

In by far the most preferred form this invention contemplates adiaphragm valve with a body having an oval diaphragm opening with theshort axis across the body and with generally circular end openings andfurther con templates that the diameters of these end openings be atleast as great as the width of the oval diaphragm opening. It alsocontemplates a body in which the seating extends along the short axis ofthe oval opening and has its ends well below the top level of thepassage end openings. In this preferred form the area of the flowpassage approaching the sea-ting from the inlet (either end opening) issharply reduced even when the diaphragm is in its fully opened position.Even though the diaphragm is of the kind having a deeply domed portionthe required shapes on the sides of the diaphragm dome and body seatingresult in a maximum flow passage area at the seating which is less thanthe end opening areas.

The performance of such valves, and others which may also be inaccordance with the invention, is particularly useful for control workbecause the characteristics of such valves more closely approach theexponential form than any prior art diaphragm valves, and suchexponential curves permit a given change in stem position to produce thesame percentage change in flow anywhere in the range of stem movement.

The importance of such flow control, as distinguished from merelyopening and closing a fluid conduit, is best understood by firstimagining an ideal valve. As stated, such a valve would be one in whicheach increment of stem movement produces the same percentage change inflow. This means that when stem movement (abscissa) is plotted againstfiow (ordin'ant) the curve rises steeply from the intersection of theaxes and then levels oif sharply, In the ideal valve the largest valueof flow (end of the curve) would seem to be the flow through a straightpiece of pipe of the size with which the valve is intended to be used.

There are, however, 'at least two reasons why it is not practical tohave control valves with the same cross-sectional flow passage area atthe seat as in the pipe with which the valve is to be used. One reasonis that even though valves can be designed which have equal percentcurves right up to such full flow rates the control of the flow in theactual system is not on such an equal percent basis because of thefriction losses in the pipe and other accessories. Unless the valve inits wide open position constitutes a substantial part of the totalsystem pressure drop an increment of valve stem movement will have arelatively small effect on total system flow. Accordingly, to assure asuitable degree of control in the valve positions near the wide openposition, it is conventional to select a valve which in its wide openposition has a crosssectional passage flow area at the seatsubstantially smaller than the full pipe cross-sectional area.

Another reason why it is not practical for a control valve to have itsflow passage area in the wide open position equal to the pipecross-sectional area is that to make such a valve have an equal percentcurve essentially involves using very large closure members andoperating them close enough to their corresponding large seats so that achange in stem position has a significant effect on flow. This hasseveral difiiculties, including the extra size of the valve toaccommodate the large parts.

Diaphragm valves have been conventionally constructed for on-off servicewith maximum flow in the wide open position, flow which approaches thatof the pipe with which the valve is to be used.

One reason for this development of the diaphragm valve has been theassumption that because of its inherent limitations an equal percentcannot be achieved throughout the range of valve movement. Moreparticularly, it has been supposed that the diaphragm quickly losescontrol of the flow as the open positions are approached. It must beborne in mind here that diaphragm valves conventionally press a closuremember (diaphragm) directly down on the seat and have not had theopportunity of progressive seating exemplified by the contoured plug ofthe plug valve. The result has been that when the diaphragm is moved arelatively small distance away from the seat the effect of furthermovement on flow becomes sharply less, and in terms of characteristiccurves the result is far from exponential and to a great extent is noteven linear.

My discovery is that, surprisingly, when the cross-sectional area of theflow passage is reduced sharply between the inlet opening and thediaphragm seat the pressure drop required in control valves is achievedin addition there is a surprising change in the conventionalcharacteristic curve toward the exponential form. A particular advantageof this improved curve is that it approaches the exponential form at thewide open position as well as elsewhere.

It might be supposed that the desirable flow characteristic abovedescribed can be achieved by merely limiting the amount of openingmovement of the diaphragm in the prior art valves of the kind having adeeply domed diaphragm. This would result in there being a sharpreduction in flow passage area. However, it is not merely the reductionalone, but the shape of the area which is important. If the seating islong, as in the prior art, a small amount of diaphragm lift produces toolarge a change in flow passage area to achieve an exponential type ofcurve. The present invention calls for a structural relationship whichnecessitates a substantial diaphragm lift to produce that same change inflow passage area.

In a preferred form of my invention the above-described desired raultsare achieved by having a diaphragm opening in the body which is oval andend openings in the body which are substantially circular and by havingthe areas of each of the end openings at least as great as the area ofan imaginary circle which has a diameter equal to the distance betweenthe seating ends. This relationship is achieved in the preferred form byhaving the rim of the diaphragm opening in the body non-planar,

by having the ends of the seating lying at a level well below the topsof the end openings, and by having the rim of the oval opening slopingfrom these seating ends to opposite points above the flow passage.

The area of the imaginary circle is an indication of the distancebetween the seating ends (which distance is the diameter of thisimaginary circle), and the distance between the seating ends determinesthe area of the actual flow passage at the seating.

The oval shape for the diaphragm opening in the body is preferredbecause it permits the actual flow passage cross-sectional area toremain as large as possible right up to the seating. This locates theflow control at the seating. A circular diaphragm opening shape may beused, but it would result in unusually steep slopes for the opening rimwhen the seating ends are maintained at about the level of the endopenings axis. This location of the seating ends near the level of thisaxis is desirable because it enables the flow over the seating to bediverted the least from its direction of movement as the valve isopened. If the rim of the diaphragm opening is located in a flat planecompletely on one side of the end openings the result is essentially aweir type valve with a deeper bulge than usual and not within the scopeof this invention. However, a diaphragm opening having its rim in a fiatplane which is below the level of the tops of the end openings, thoughnot preferred, is within the scope of the present invention.

In diaphragm valves of the kind to which this invention relatesnon-circular body end openings are not common, and in those non-circularend openings which may be used the maximum dimension is not likely to bevery different than the minimum dimension. Accordingly I have found thatby having the maximum dimension of the end opening always greater thanthe distance between the seat ends the desired reduction in flow passagearea will obtain as a practical matter.

It is more common to have non-circular passage portions inwardly of theend openings, but here again the maximum and minimum dimensions of suchportions are not very different in practice, and as long as the maximumdimension along the passage portion is greater than the distance betweenthe seat ends the reduction in flow passage area can be expected as apractical matter.

Accordingly, it is one object of the present invention to provide adiaphragm valve of the kind having a deeply bulged diaphragm centerportion and having seating ends which are below the level of the tops ofthe end openings in which the flow passage therethrough has itscrosssectional area sharply reduced between the inlet opening and theseat.

Another object is to provide a diaphragm valve of the kind described inwhich a certain relationship between the diaphragm opening in the bodyand an end opening in the body provides the desired sharp reduction inflow passage area.

Another object is to provide a diaphragm valve of the kind described inwhich the area of a body end opening is at least as great as the area ofa circle having a diameter equal to the distance between the seatingends.

Another object is to provide a diaphragm valve of the kind described inwhich the body end openings are circular and the body diaphragm openingis oval with its short axis disposed across the body and with thediameters of its end openings at least as great as the length of thisshort axis.

Another object is to provide a diaphragm valve of the kind described inwhich the reduction in the crosssectional area. of the flow takes placecloser to the seat than to the inlet opening.

Another object is to provide a diaphragm valve of the kind described inwhich the greater part of the reduction in cross-sectional area of theflow passage takes place immediately adjacent the seat.

Another object is to provide a diaphragm valve of the kind firstdescribed in which the diaphragm opening is generally circular and hasan area not substantially greater than the cross-sectional area of thepassage at the inlet opening.

Another object is to provide a diaphragm for which the characteristiccurve resulting from a plot of flow against stem position for a constantpressure drop approaches closer to an exponential form than previous diaphragnnv valves.

Another object is to provide a novel diaphgram valve which isparticularly useful as a control valve, but which employs many partspreviously used in prior art valves.

Another object is to provide a noval diaphragm valve which isinexpensive to manufacture, etficient in operation easy to install andservice.

Other objects will appear hereinafter.

The best mode in which it has been contemplated applying the principlesof the present invention are to be found in the accompanying drawingsbut these are to be deemed primarfly illustrative for it is intended tocover by suitable expression in the appended claims Whatever ofpatentably novelty exists in the invention disclosed.

In the drawings:

FIGURE 1 is a cross-sectional side elevation view of a valve which isone embodiment of the present invention, the valve being shown in theopen position;

FIGURE 2 is a cross-sectioned end elevation view taken on line 22 ofFIG. 1;

FIGURE 3 is a partially sectioned, exploded, perspective view of thebody and diaphragm of the valve of FIGS. 1 and 2;

FIGURE 4 is a top plan view of the body alone; and

FIGURES 5, 6 and 7 are views like FIGS. 1, 2 and 4, but showing anotherembodiment of the invention.

Referring now more particularly to the drawings, the embodiment of FIGS.1 to 4 shows that the rim 10 around the diaphragm opening 12 in the body14 is generally saddle shaped, being lower at the sides 16- of the bodythan in the middle. As a result the weir ends 18 are, of course, locatedat a level (plane 19) well below the tops of body end openings 20 and22. Plane 19 is substantially parallel to axis 24 of the circular endopenings 20 and 22 and intersects a substantial part of the flowpassage. Preferably the plane 19 includes axis 24.

Weirs shaped like the one in this embodiment of FIGS. 1 to 4 have beenknown in the past, but to my knowledge, they have always been soproportioned relative to the cross-sectional area of the flow passagethat there has been either increase in such area at the seating when thevalve is opened or, at least, no smaller an area at the seating thananywhere else along the passage. In ac cordance with the presentinvention the ends of the diaphragm seating (weir ends 18) are spacedapart by a distance which is sutficiently short with respect to thedimensions of the end openings that during opening of the diaphragm thecharacteristic flow curve is or approaches the exponential form, or,more particularly, the distance between the seating ends is sufficientlyshort with respect to the dimensions of the end openings that even whenthe diaphragm is as wide open as it can be (without any kinds of stops)the area of the flow passage at the seat ing is nevertheless far smallerwith respect to the areas of each of the end openings than in the priorart. Such relationships are satisfied when the area of each of the end oenings 20 and 22 is at least as great as the area of a circle 27 havinga diameter 29 equal to the distance between the seating ends 18. This isbest seen in the end view of FIG. 2 where the circular end opening isindicated by dotted line 20.

Because the seating in this embodiment has such a deep concavity thecenter 28 of the diaphragm 30 is very thick and has a generallysemi-spherical shape which fits the center of the seating 32. The sides34 of the seating slope steeply upward from this center to the open rim10. From its center 28 the flexible diaphragm walls 36 extend 6 to theclamped peripheral portion 38. In FIG. 2 these walls are in a rathersharply rolled configuration in the open position, the rolls being suchthat the required movement is able to take place to close the valve. InFIG. 1 the rolled configuration is less sharp because the clamped marginin this view While higher up is also farther out. The result is a smoothflow line as indicated by arrow 40. Arrow 4-2 shows how the flow issmoothly guided through the pockets 44 at the weir and resulting fromthe rolled configuration.

To simplify securing of the bonnet 46 to the body only two bolt and nutassemblies 48 are used, it being understood, however, that additionalsuch assemblies may be used around the periphery of the diaphragm. Thetwo bolt and nut assemblies pass through cooperating extensions St), 38and 52 on the body, diaphragm and bonnet respectively, each havingsuitable holes. The compressor arrangement is as shown with thecompressor underside 54 shaped to conform to the diaphragm in open andclosed position. The actuating details of the bonnet and compressor arethe same as in the prior art.

' One advantage of this kind of opening which dips down at the weir isthat it provides a less abrupt change in direction of flow in the openposition. Even though this opening is small relative to the end openingsit would still provide good passage for a heavy viscous fluid or a fluidwith suspended solids.

FIGS. 5, 6 and 7 show another embodiment which is like that of FIGS. 1to 4 except that the diaphragm opening 60 is circular rather than ovaland the rim 62 of the diaphragm opening lies in a fiat plane 64, ratherthan being saddle-shaped. As a consequence the diaphragm 66 is the samein its several elevation view cross-sections, and the upper wall of thebody flow passage dips down quite suddenly at 67 as it approaches thediaphragm opening 60 from either of the end openings 68 or 70. As in theembodiment of FIGS. 1 to 4, the flow through the valve when thediaphragm is open produces a diversion of both the upper and lowerportions of the flow because the plane 64 is set below the top level(72) of the end openings. Arrows 73 and 74 show this diversion.

FIG. 6 shows particularly well the comparison of flow passage area atthe seating with the area of the end opening.

I claim:

1. A diaphragm valve having:

(I) an elongated hollow body having:

(A) walls which:

( 1) define valve body sides, (2) terminate in opposite valve body ends,(3) have interior surfaces defining a fiow passage, (B) a long dimensionmeasured between said ends, (C) a diaphragm opening which:

(1) is located in one of said valve body sides, (2) extends through saidwalls, (3) has a rim which:

(a) extends around opening, (b) has opposite portions lying in a firstplane which:

(i) is parallel to said long dimension, (ii) intersects a substantialpart of said flow passage, (4) has a width dimension measured:

(a) across said opening, (b) between said rim portions, (c) at rightangles to said long dimension, (D) a diaphragm seat which:

(1) is located:

(a) on said interior wall surfaces, (b) between said valve body ends,(c) opposite said diaphragm opening,

said diaphragm (2) has two separate portions which:

(a) are sloped steeply with respect to said first plane, (b) have theirouter ends merging into said diaphragm opening rim portions, (3) has acenter portion connecting said separate portions, (E) an end openingwhich:

(1) is located at one of said body ends, (2) lies in a second plane atsubstantially right angles to said long dimension, (3) has an area whichis at least as great as the area of an imaginary circle having adiameter equal to said diaphragm opening width dimension,

(II) a flexible diaphragm which:

(A) has an outer portion in contact with said body rim,

(B) has a center portion which covers said body diaphragm opening,

(III) means for permanently clamping the diaphragm outer portion againstsaid body opening rim up to said diaphragm opening,

(IV) means for moving said diaphragm center portion with respect to saiddiaphragm seat portions to different positions from fully closed tofully open, said diaphragm center portion,

(A) when in fully open position forming with said seat portions a flowopening, measured in a plane parallel to said second plane, which isconsiderably less in area than said end opening area.

2. A diaphragm valve according to claim 1 wherein said end opening issubstantially circular.

3. A diaphragm valve according to claim 2 wherein a second end openingis located at the other of said body ends, wherein said second endopening is also substantially circular and wherein said end openingshave substantially the same diameter.

4. A diaphragm valve according to claim 3 wherein said diaphragm openingin the body is oval with the short axis of the oval disposed atsubstantially right angles to said long dimension.

5. A diaphragm valve according to claim 4 wherein said diaphragm openingrim portions are located at the ends of the oval short axis wherein saidrim has additional opposite portions lying in a third plane which isparallel to said first plane and which lies outside said flow passage,and wherein said rim slopes with respect to said first and third planesas it extends between its said first and second portions.

6. .A diaphragm valve according to claim 5 wherein said first planesubstantially passes through the axis joining the centers of saidcircular end openings.

7. A diaphragm valve according to claim 3 wherein said diaphragm openingin said body is substantially circular and wherein the diameter of saidcircular diaphragm opening is at least as small as the diameter of saidend openings.

' 8. A diaphragm valve according to claim 7 wherein substantially theentire rim of said diaphragm opening in said body lies in said firstflat plane.

9. A diaphragm valve according to claim 3 wherein said first flat planepasses substantially through the axis joining the centers of saidcircular end openings.

10. A diaphragm valve according to claim 1 wherein said means forpermanently clamping said diaphragm outer portion against said bodyopening rim comprises a bonnet secured to said body and wherein saidmeans for moving said diaphragm center portion comprises a compressormovably mounted in said bonnet and secured to said diaphragm.

References Cited by the Examiner UNITED STATES PATENTS 2,716,017 s/1955Linker 251 331 2,853,270 9/1958 Boteler 251 331 FOREIGN PATENTS 639,4539/1962 Canada.

ALAN COHAN, Primaly Examiner.

1. A DIAPHRAGM VALVE HAVING: (I) AN ELONGATED HOLLOW BODY HAVING: (A)WALLS WHICH: (1) DEFINE VALVE BODY SIDES, (2) TERMINATE IN OPPOSITEVALVE BODY ENDS, (3) HAVE INTERIOR SURFACES DEFINING A FLOW PASSAGE, (B)A LONG DIMENSION MEASURED BETWEEN SAID ENDS, (C) A DIAPHRAGM OPENINGWHICH: (1) IS LOCATED IN ONE OF SAID VALVE BODY SIDES, (2) EXTENDSTHROUGH SAID WALLS, (3) HAS A RIM WHICH: (A) EXTENDS AROUND SAIDDIAPHRAGM OPENING, (B) HAS OPPOSITE PORTIONS LYING IN A FIRST PLANEWHICH: (I) IS PARALLEL TO SAID LONG DIMENSION, (II) INTERSECTS ASUBSTANTIAL PART OF SAID FLOW PASSAGE, (4) HAS A WIDTH DIMENSIONMEASURED: (A) ACROSS SAID OPENING, (B) BETWEEN SAID RIM PORTIONS, (C) ATRIGHT ANGLES TO SAID LONG DIMENSION, (D) A DIAPHRAGM SEAT WHICH: (1) ISLOCATED: (A) ON SAID INTERIOR WALL SURFACES, (B) BETWEEN SAID VALVE BODYENDS, (C) OPPOSITE SAID DIAPHRAGM OPENING, (2) HAS TWO SEPARATE PORTIONSWHICH: (A) ARE SLOPED STEEPLY WITH RESPECT TO SAID FIRST PLANE, (B) HAVETHEIR OUTER ENDS MERGING INTO SAID DIAPHRAGM OPENING RIM PORTIONS, (3)HAS A CENTER PORTION CONNECTING SAID SEPARATE PORTIONS, (E) AN ENDOPENING WHICH: (1) IS LOCATED AT ONE OF SAID BODY ENDS, (2) LIES IN ASECOND PLANE AT SUBSTANTIALLY RIGHT ANGLES TO SAID LONG DIMENSION, (3)HAS AN AREA WHICH IS AT LEAST AS GREAT AS THE AREA OF AN IMAGINARYCIRCLE HAVING A DIAMETER EQUAL TO SAID DIAPHRAGM OPENING WIDTHDIMENSION, (II) A FLEXIBLE DIAPHRAGM WHICH: (A) HAS AN OUTER PORTION INCONTACT WITH SAID BODY RIM, (B) HAS A CENTER PORTION WHICH COVERS SAIDBODY DIAPHRAGM OPENING, (III) MEANS FOR PERMANENTLY CLAMPING THEDIAPHRAGM OUTER PORTION AGAINST SAID BODY OPENING RIM UP TO SAIDDIAPHRAGM OPENING, (IV) MEANS FOR MOVING SAID DIAPHRAGM CENTER PORTIONWITH RESPECT TO SAID DIAPHRAGM SEAT PORTIONS TO DIFFERENT POSITIONS FROMFULLY CLOSED TO FULLY OPEN, SAID DIAPHRAGM CENTER PORTION, (A) WHEN INFULLY OPEN POSITION FORMING WITH SAID SEAT PORTIONS A FLOW OPENING,MEASURED IN A PLANE PARALLEL TO SAID SECOND PLANE, WHICH IS CONSIDERABLYLESS IN AREA THAN SAID END OPENING AREA.